input device with the output device or vice-versa. In order to make it simpler, Intel has designed A chip to interface I/O devices. The Intel A is a general. A Programmable Peripheral Interface in Microprocessor – A Programmable Peripheral The following figure shows the architecture of A −. The (or i) programmable peripheral interface (PPI) chip was developed and manufactured by Intel The PPI chip Architecture.

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Embedded C Interview Questions. Memory Access Assembler Tutorial for Beginner All of the output registers, including the status flip-flops, will be reset whenever the mode is changed. Digital Electronics Practice Tests. This has an 8-bit latched and cchip output and an 8-bit input latch. This 3-stable bi-directional 8-bit buffer is used to interface the A to the systems data bus. Digital Electronics Interview Questions.

This allows a single A to service a variety of peripheral devices with a simple software maintenance routine. Address lines A 1 and A 0 allow to access a data register for each port or a control register, as listed below:.

Retrieved 3 June Inputs are not latched. The two halves of port C can be either used together as an additional 8-bit port, or they can be used as individual 4-bit ports.

All can be configured to a wide variety of functional characteristics by the system software but each has its own special features or “personality” to further enhance the power and flexibility of the The i was also used with the Intel and Intel [1] and their descendants and found wide applicability in digital processing systems.


Mode 1 Basic Functional Definitions: How to design your resume? Outputs are not latched. Intel Programmable Interval Timer.

The control logic block accepts control bus signals as well as inputs from the address bus, and issues commands to the individual group control blocks Group A control and Group B control. Port A can be used for bidirectional handshake data transfer.

You get question papers, syllabus, subject analysis, answers – all in one app. If bit 7 of the control word is a logical 0 then each bit of the port C can be set or reset.

Each of the Group A and Group B control blocks receives control words from the CPU and issues appropriate commands to the ports associated with it.

Each line of port C PC 7 – PC 0 can be set or reset by writing a suitable value to the control word register. In essence, it allows the CPU to “read from” the Analogue electronics Practice Tests.

Intel A Programmable Peripheral Interface

Both “pull-up” and “pull-down” bus-hold devices are present on Port A. Learn Microprocessor in simple and easy steps starting from basic to advanced concepts. After the reset is removed the A can remain in the input mode with no additional Initialization required. Interview Tips 5 ways to be authentic in an interview Tips to help you face your job interview Top 10 commonly asked BPO Interview questions 5 things you should never talk in any job interview Best job interview tips for job seekers 7 Tips to recruit the right candidates in 5 Important interview questions techies fumble most What are avoidable questions in an Interview?


Digital Logic Design Interview Questions.

The functional configuration of the A is programmed by the systems software so that normally no architectur logic is necessary to interface peripheral devices or structures. It was later cloned by other manufacturers. All information read from and written to the occurs via these 8 data lines.

Embedded Systems Practice Tests. This mode is selected when D 7 bit of the Control Word Register is 1.

Intel 8255

Group A and Group B Controls. Definition of Architectuure 1. Control words and status informa-tion are also transferred through the data bus buffer. Views Read Edit View history. Making a great Resume: This port can be divided into two 4-bit ports under the mode control. By using this site, you agree to the Terms of Use and Privacy Policy. Ports A, B, and C.

Evolution of Microprocessor History of the microprocessor! Used in Group A only.

The Control Word Register can only be written into. Digital Logic Design Practice Tests.

If this line is a logical 0, the microprocessor can read and write to the They are normally connected to the least significant bits of the address bus A0 and A1.

So, without latching, the outputs would become invalid as soon as the write cycle finishes.